What are the symptoms of vertebrobasilar insufficiency syndrome or steal syndrome?

Symptoms of Vertebrobasilar Insufficiency Syndrome or Steal Syndrome

Vertebrobasilar insufficiency syndrome presents with a characteristic constellation of symptoms including dizziness, vertigo, visual disturbances, diplopia, ataxia, and syncope that occur due to compromised blood flow in the posterior circulation of the brain.

Clinical Presentation

Vertebrobasilar insufficiency (VBI) and steal syndrome typically manifest with the following symptoms:

Primary Symptoms

• Dizziness and vertigo (31-50% of cases) 1, 2
• Visual disturbances including:
  • Blurred vision
  • Diplopia (double vision)
  • Amaurosis fugax (temporary vision loss)
  • Visual field defects 1
• Balance problems:
  • Ataxia (impaired coordination)
  • Gait instability 1, 3
• Syncope or near-syncope (30% of cases) 2

Additional Neurological Symptoms

• Sensory symptoms:
  • Perioral numbness
  • Bilateral sensory deficits 1
• Speech disturbances:
  • Dysarthria (slurred speech)
  • Dysphasia (impaired language ability) 1
• Motor symptoms:
  • Weakness (potentially bilateral)
  • Alternating hemiparesis 1
• Cognitive changes:
  • Confusion
  • Mental status alterations 1

Specific Features of Subclavian Steal Syndrome

Subclavian steal syndrome, a specific form of VBI, has distinctive characteristics:

• Position-dependent symptoms that worsen with:
  • Arm exercise on the affected side
  • Head rotation or extension 1, 4
• Exercise-induced symptoms in the upper extremity:
  • Arm claudication
  • Fatigue
  • Pain during arm exertion 1
• Symptoms triggered by specific movements:
  • Head turning (especially in Bow Hunter's syndrome)
  • Neck extension 4, 5
• Resolution of symptoms when:
  • Returning to upright position
  • Flexing the neck 4

Clinical Variants and Associations

• Subclavian steal with myocardial ischemia in patients with internal mammary artery coronary bypass grafts 1
• Bow Hunter's syndrome - occlusion of vertebral artery with head rotation 5
• Hemodialysis-related steal in patients with arteriovenous access 6

Diagnostic Considerations

The diagnosis of VBI should be considered in patients with:

• Blood pressure difference >15 mmHg between arms (highly suspicious for subclavian stenosis) 1
• Pulsatile neck mass 1
• Symptoms that worsen with upper extremity exertion 1
• Periclavicular or infraclavicular bruit 1

Pitfalls and Caveats

1. Symptom overlap with other conditions: Many VBI symptoms can be caused by other disorders including:

   • Cardiac arrhythmias
   • Orthostatic hypotension
   • Vestibular disorders 1
   • Migraine

2. Asymptomatic disease: Subclavian stenosis can be asymptomatic in approximately 4.5% of adults, with higher prevalence (11.4%) in patients with peripheral arterial disease 1

3. Intermittent nature: Symptoms may be transient and positional, making diagnosis challenging without appropriate provocative testing 4

4. Diagnostic confirmation: While symptoms are suggestive, definitive diagnosis requires demonstration of flow reversal in vertebral arteries or hemodynamic compromise during symptomatic positions 1, 4

Understanding these characteristic symptoms is crucial for early recognition and appropriate management of vertebrobasilar insufficiency syndrome, as timely intervention can prevent serious complications including posterior circulation stroke.